As used herein, the terms "pipe segments" and "well pipes" can be used to refer severally to drill pipes, drill collars, casings, production tubing, and the like such as may be used in drilling and production operations.
In such operations, lengths of individual downhole tubulars are connected in order to make a string of downhole tubulars necessary for the particular application. The connection of lengths of downhole tubulars to make a string is referred to as "making up" and the disconnection of a string is referred to as "breaking down". The equipment for making up and breaking down a string of downhole tubulars is located on the surface adjacent to the drill hole typically on a drilling floor.
The making up of a string of pipe segments for the purpose of making the well pipe requires the lifting and aligning of an individual length of pipe segment to be added to another pipe segment. Typically, this means that the length of pipe segment to be added is suspended over, aligned and then connected to the well pipe (which may be part of a string of downhole tubulars which may be partially beneath the surface of the earth). The pipe segment to be added may be connected to the well pipe already in place by threading the two of them together either directly or with a coupling. This making up operation necessarily requires that the pipe segment be added must be centered and rotated with respect to the well pipe while the pipe segment is suspended.
Typically, several different diameters of pipe segments are used on such an operation. For example, a production tube may be two and seven-eighths inches in diameter, a drill pipe may be three to twelve inches in diameter, and a casing may be up to thirty-two inches in diameter. As explained above, with respect to each of these different types and different diameters, it is necessary to center the pipe segment and rotate it in order to make up a string. Accordingly, although the centering and rotating may be done by separate devices, it is more efficient if one device could be provided that is able to both center and rotate the variety of pipe segments.
In the past, various patents have issued relating to such a spinning apparatus. For example, U.S. Pat. No. 3,799,009, issued on Mar. 26, 1974 to W. Guier, teaches an apparatus for threading and unthreading vertical lengths of drill pipe. This apparatus includes a backup tong removably positioned around a lower drill pipe, a spinner removably positioned around an upper drill pipe, and a lead tong removably positioned around the upper drill pipe. A piston-and-cylinder arrangement is provided so as to pivot several arms so that a clamping operation can occur for the purposes of the backup tong. Another hydraulic cylinder is mounted on a frame so as to actuate several levers so as to place a chain around the exterior of the drill pipe for the purpose of spinning the drill pipe. Unfortunately, this device has no centralization effect and does not reach so as to draw the drill pipe into a central area. This device can only be used on a single diameter of pipe and must be adapted to the various other diameters of pipe which are to be installed in the well.
U.S. Pat. No. 4,005,621, issued on Feb. 1, 1977, to Turner, Jr. et al., teaches a drilling tong having an open head portion and means for adjustably engaging the peripheral portions of workpieces. The drilling tong has an open area into which the drill pipe is inserted. A hydraulic cylinder, mounted on the tong, can actuate several arms and linkages so as to close the clamping elements onto the exterior surface of the pipe. A spring is used to open the jaw. This device lacks a centralizing effect and does not include the mechanism for spinning the pipe. Since the device utilizes teeth on each of the clamping areas, the teeth may actually support the pipe in an undesired position rather than a centralized position.
U.S. Pat. No. 4,446,761, issued on May 8, 1984 to Boyadjieff et al., teaches a pipe spinning tool having two body parts carrying rollers adapted to engage a pipe at different locations around its periphery and to grip and spin the pipe by rotating one or more of the rollers. The two body parts are mounted by pivotal connections for swinging movement about two spaced axes respectively to grip and release the pipe. An adjustable connection attaches the two pivotal connections together for relative lateral adjusting movements to shift their pivotal axes toward and away from one another for gripping different sizes of pipes. This device is a commonly known spinner used in the commercial market. It does not have a centralizing effect. As such, in order to properly center the drilling pipe in a desired location, the frame of the mechanism must be moved backward and forward and the drill pipe must be centered above the well pipe. Additionally, manual efforts are required to place the pipe segment between the rollers.
U.S. Pat. No. 5,054,550, issued on Oct. 8, 1991 to L. R. Hodge, teaches a centering spinner for centering and spinning downhole tubulars having a range of diameters. The centering spinner includes a frame capable of admitting a downhole tubular therein and a plurality of roller assemblies pivotally coupled to the frame to converge upon and center the downhole tubular. Adjacent rollers of the roller assemblies of the centering spinner are axially displaced with respect to a downhole tubular retained therein. Although this device is designed for centering, it can only center within a limited area. There is no mechanism for drawing the pipe into the spinning area. If the pipe is too deep within the receiving area, the spinning rollers cannot reach it.
U.S. Pat. No. 5,000,065, issued on Mar. 19, 1991, to C. W. Haynes, describes a jaw assembly for gripping pipes such that the jaws cooperate so as to center the pipe. U.S. Pat. No. 5,778,742, issued on Jul. 14, 1998, to R. L. Stuart, describes a hydraulic backup tong assembly which provides for the gripping of the drill pipe. U.S. Pat. No. 5,791,206, issued on Aug. 11, 1998, to Daigle et al., teaches a wrench for making drill pipe segments. The wrench is arranged so as to center the gripping jaws upon the drill pipe.
The rollers which are used with prior art spinner apparatus have a number of problems. Typically, these rollers are formed of a steel material which will contact the pipe in compressive relationship so as to properly rotate the pipe. Unfortunately, the steel rollers are relatively expensive. The hard material which forms the steel rollers can often damage a pipe segment during the compressive contacting of the steel roller with the pipe. If the roller is sufficiently damaged, then it must be entirely replaced and a new roller installed. The steel rollers are difficult to manufacture. Also, steel rollers commonly will have a smooth outer surface. When the pipe has oil or other friction-reducing materials thereon, it is often difficult to achieve a strong frictional contact between steel rollers and the outer surface of the pipe segment.
There are other problems associated with the use of aluminum rollers. These aluminum rollers will wear more quickly than the steel rollers. The edges will tend to fray after continuous use of such aluminum rollers. Because of the rapid wearing of the outer surface of such aluminum rollers, replacement of the rollers must be carried out relatively frequently. In view of the high cost associated with the installation of such pipe segments, any down time associated with the repair of such aluminum rollers could adversely affect the cost of the well. Aluminum rollers are also susceptible at low friction contact with a pipe segment when the pipe segment is covered with oil or a lubricating material. When an aluminum roller must be replaced, the entire roller must be replaced and a new roller installed thereon.
It is another object of the present invention to provide a roller for a spinner apparatus which establishes a strong frictional contact between the outer surface of the roller and the surface of the pipe segment.
It is an object of the present invention to provide a roller for a spinner apparatus which can be easily repaired.
It is another object of the present invention to provide a roller which resists wearing and avoids the fraying of the outermost edges.
It is another object of the present invention to provide a roller for a spinner apparatus which is relatively inexpensive.
It is still a further object of the present invention to provide a roller for a spinner apparatus which will work effectively in an oil or lubricant-filled environment.
It is still a object of the present invention to provide a roller for a spinner apparatus which avoids steel-to-steel contact with the pipe segment.
It is still a further object of the present invention to provide a roller for a spinner apparatus which avoids damage to the pipe segment.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.